Interstitial cystitis (IC) is characterized by chronic and debilitating bladder pain, usually accompanied by urinary frequency and urgency. Because research has been hampered by the lack of a clear and well accepted case definition, little is known about the prevalence of 1C in the population, the full burden of disease for IC patients, the kinds of care they seek, and the kinds of treatment they receive. At present, there is no standardized questionnaire for patient screening or epidemiological studies. The lack of information about IC makes it difficult to meet patients' needs for medical and non-medical care. In the proposed research, therefore, we will establish (1) a case definition of IC in women for patient screening or epidemiological studies using a Delphi panel of experts in IC and diseases with similar symptoms; (2) develop and validate a symptom questionnaire that can be used to identify female IC patients and distinguish them from those with similar conditions (e.g., overactive bladder, urinary tract infection, and endometriosis); (3) develop an IC-specific measure of self-reported functional status, including physical, mental, social, sexual/relationship, role functioning and other factors identified by IC patients as important; (4) survey more than 300,000 women for urinary symptoms and, using the validated symptom questionnaire, screen more than 23,000 to estimate prevalence of IC in the United States and provide a sample of 354 women over age 18 who fit the case definition for IC and 300 who have IC-like symptoms; (5) describe the impact of IC on patient's lives, including IC-specific functional status and the impact of IC on quality of life, mental and physical health, stress and coping, social support, sexual functioning, social functioning, labor force participation and income, as well as utilization of traditional and alternative care and compare these results with existing data on disease burden for other chronic diseases.